Preparation of camphene from pinene



UNITED STATES" PATENT OFFICE PREPARATION on OAMPHENE moiu rmahm wmim F. Carson, Jr., Brunswick, Ga., assinor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application July 21, 1943, Serial No. 495,648

1:. Claims. (01. 2606'l5.5)

This invention relates to improvements in terpene isomerization and more particularly, to a new catalytic processior the preparation of camphene from pinene.

Camphene is an important chemical or induswas cooled, filtered to remove the catalyst, and the filtrate fractionated. A yield of 60% of solid camphene was obtained, the remainder of .the material being chiefly monocyclic terpenes.

. Example II try, from which many products of commerceare v made, one of which is camphor. Many methods h above Procedure was repeated but have been suggested in the literature for t prep.. ninite was used as the catalyst. A yield of 59% auction of camphene from bomyl chloride, each o i a p e e was obtainedmethod attempting to produce a chlorine-free Example 111 product. Attempts to produce chlorine-free cam- Example I was duplicated but clinocblore was phene have led to the development of various oneh all d m f 61 7 I M step methods using a catalyst to promote the isoused as e cat yst an yie 0 so merization o! pinene directly to camphene, thus w obtained eliminating the bornyl chloride stage. Mahy The chlorites operable as a catalyst in accordmethods have been suggested using various types 'ance with this invention are silicates of magnesof catalysts, both organic and inorganic. as well iuin or iron, usually occurring in scaly ag r ates as mineral to effect this one-step conversion of 1 and being softer than the micas and pliable inpinene directly to camphene. In all cases where stead of being elastic. According to Paulings exorganic or inorganic type catalysts are used, the planation of the chlorite structure, it consists of yield of desirable product has been relatively alternate mica-like and brucite-like layers. The

low as, for example, in the neighborhood of about mica-like layers have a composition varying be- 15%. Of the mineral catalysts many are no tween Mg: (AlSiaOm) (OH): and better than the organic and/or inorganic types, MgzAKAhSiaOm) (OH): while others permit yields of camphene as high and the brucite-like layers, the composition as 50% but only after a comparatively long re- Mg2A1(OH)e.

. action period. 1 Each of the specific minerals that may be grouped Now, in accordance with the present invention. and referred to as the chlorites may be repreanew catalytic process has been discovered where-v sented by a type structural fromula varying from in it has been found that the specific group of Ii' H 2Mgc-(OH) 2O4.'A1Si30s] silicatesknown as the chlorites, will promote the [(OH) 8'A12Mg4' (OH) 5] isomerization of isomerizable terpenes. In parto v ticular it has been discovered that this specific [Os'A12Si2 O4(0H)s-AIzM c-(0H) 204-1812812061 group of silicates will effect the production of 5 H)c-Al2M84- 0H)c]- relatively high yields of pure camphene in a rel- 3 The 011101711795 Operable in accordance with gflvely short period of t when u as an this invention include those chlorites resulting isomerization catalyst in the presence of an r m m rphous sti ut nsn th ab ve typ isomerizable terpene. formula where, for instance, Fe" and Mn" may The method in accordance with this invention 40 replace nd Fe may replace Al', in six is m twt by ,t du m ifi examples, coordination. (See Bragg, Atomic Structure of all parts and percentages being by weight unless .Minerals," page 219.) Specific chlorites found otherwi specified; especially applicable in accordance with this in- Example I vention are known by the mineral names, prov chlorites, clinochlore, and penninite.

A quantity of the mineral catalyst, prochlorite, The specific chlorite catalyst, prochlorite, used was dried for one hour at C. and then pulin Example I may be further characterized as verized to a grain size oi about 28 mesh. One having ahardness (Mohs scale) of between 1 and part of this mineral catalyst was slowly added to 2, a refractive index of 1.58, a small and variable 43 parts of alpha-pinene having a specific gravity to optic a ial a le. a f b y p rly luster, and a of .8646 which was held at the reflux temperature green rochlorite is further characterized until addition of the catalyst was complete. The as ha n flexi le lamin whi h do n t exfoliate mixture was refluxed gently for two hours, during pprecia ly on heating- The other chlorites are Y which time the temperature of the reaction mixsimilarly rized 'ture had risen from 156 C- C. The mixture 55 The chlorites operate as catalysts in the lump or unground form but are preferably used in the ground form for purposes of conversion, convenience of use, and uniformity of reaction. Although reaction rates inoreasewith increase in fineness of the catalyst, little eflect of fineness is noticed above a grain size of about 200 mesh.

Thenovel catalytic conversion of an isomerizable terpene to camphene may be carried out between'about 50 C. and about the reflux tem: perature of the terpene being treated. The preferred operating range. is between about 15 5 .0. and about 167 C. at normal atmospheric pressure. Under proper-conditions of pressure, temperatures up to 200 C. or higher may be used.

Catalytic conversion of terpene to camphene may be made in a relatively short. period of time, when using the chlorite minerals or when using a rock or a mineral product containing essentially the chlorites. When alpha-pinene was isomerized in accordance with the method of Example I, it was found that a 90% conversion of the pinene was efiected at the given temperature in minutes to give a yield of about 63% camphene, based on total pinene used. The reaction time may vary between about 10 minutes and about 8 hours. Completeness of isomerization of pinene is desirable. When the reaction is not carried to com-' wood turpentine, sulfate turpentine which is obtained in the manufacture of paper from the delignification of wood, etc.

. The ratio of chlorite catalyst used to the'terpene being treated may vary between about 0.005 and about 0.1 and is preferably between about 0.015 and about 0.025.

The process in accordance with this invention may be carried out as a batch process in liquid or vapor phase or as a continuous process in these same phases.

From the foregoing description, it is apparent that a new method of producing pure camphene in an efiicient, effective, and economical manner has been discovered, wherein a terpene capable of being isomerized may be directly converted to camphene in a relatively short period of time by 55 heating the terpene in the presence of a chlorite or a mineral productor rock containing essen- .tially a. chlorite.

What I claim and desire to protect by Letters Patent is:

. 1. The process of isomerizing a pinene-contain- .ing material, which comprises heating said mate- 5 rial in the'presence of a chlorite until lsomeriza- I tion is at least partially complete.

2. Th process of isomerlzing a pinene, which comprises heating a pinene in the presence of a chlorite until isomerization is at least partially 10 complete. a

3. Theprocess of isomerlzing a pinene, which comprises heating the-pinene in the presence of prochlorite until isomerization is at least partially complete.

4. The process of ,isomerizing a pinene, which comprises heating the pinene in the presence of penninite until isomerization is at least partially complete.

5. The process of iscmerizing a pinene, which comprises heating the pinene in the presence of clinochlore until isomerization is at least partially complete.

6. The process of isomerizing alpha-pinene,

which comprises heating alp -pinene in the presence of a chlorite until iso erization is at least partially complete.

1 '7. The process of isomerizing alpha-pinene, which comprises heating. alpha-pinene in the presence of prochlorite until isomerization is at least partially complete.

8. The process of isomerizing alpha-pinene, which comprises heating alpha-pinene in the presence of penninite until isomerization is at least partially complete.

9. The process of isomerizing alpha-pinene,-

which comprises heating alpha-pinene in the presence of clinochlore until isomerization is at least partially complete.

10. The process of isomerizing turpentine, 40 which comprises heating turpentine in the presence of a chlorite until isomerization is at least partially complete.

11. The process of isomerizing turpentine, which comprises heating turpentine in the presence of prochlorite until isomerization is at least partially complete.

12. The process of isomerizing turpentine, which comprises heating turpentine in the presence of penninite until isomerization is at least partially complete. a

13. The process of isomerizing turpentine, which comprises heating tiupentine in the presence of clinochlore until isomerization is at least partially complete.

WILLIAM F. CARSON. JR.

7 CERTIFICATE OF CORRECTION. Patent No. 3,3 2, 97. Au u t 11;, 191

- WILLIAM F. CARSON, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, line 17, for "of iron'{ read --and. iron----; and. that the said Letters Patent should be read'with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 20th day. of November, A. -D. 1915.

Leslie Frazer (Seal) First'hesistant Commissioner of Patents. 

